《简单机械和功》这一章有两个重点的实验,是中考考查的重点,也是学习的难点。下面将对两个实验中的几个问题作理解和分析。一、探究杠杆的平衡条件1.为什么要将杠杆调节在水平位置平衡?如何调节?分两种情况讨论:(1)实验前,调节杠杆在水平位置平衡,使杠杆的重心恰好落在支点上,消除杠杆自重对杠杆平衡的影响。通过调节杠杆两端的平衡螺母,若右端高了,两端的螺母都向右调节;若左端 The chapter “Simple Mechanics and Power” has two key experiments, which are the key points of the middle school entrance exams and the difficulties of learning. The following will be two experiments in a few questions to understand and analyze. First, to explore the balance of leverage conditions 1 why the lever position adjustment in the horizontal position? How to adjust? Divided into two cases to discuss: (1) before the experiment, adjust the lever balance in the horizontal position, so that the lever’s center of gravity just fell on the fulcrum , Eliminating the leverage of leverage on the balance of the impact. By adjusting the balancing nut at both ends of the lever, if the right end is high, both ends of the nut are adjusted to the right; if the left end